YOSEMITE NATIONAL PARK, California (AP) — A destructive wildfire on the outskirts of Yosemite National Park that is threatening some 2,500 structures has grown to some 15 square miles (39 square kilometers) and forced the shutdown of a highway into the park.

The San Francisco Chronicle reports some 200 seniors were forced to evacuate Tuesday from Camp Mather, which is owned and operated by the city of San Francisco and was hosting a special week for the elderly.

The fire started Saturday and has destroyed two residences and five outbuildings. It has also forced a few dozen people to leave the tiny community of Buck Meadows.

The U.S. Forest Service says State Route 120 is shut down in both directions, blocking traffic in and out of Yosemite on its west side, but the park remains open.